/* --- CSS Variables for Theming --- */
:root {
    --bg-color: #f0f2f5;
    --container-bg: #ffffff;
    --text-color: #1c1e21;
    --border-color: #d1d5db;
    --accent-color: #007bff;
    --accent-hover: #0056b3;
    --board-bg: #e9ecef;
    --cell-bg: #ffffff;
    --cell-hover-bg: #f8f9fa;
    --p1-token-color: #dc3545;
    --p2-token-color: #17a2b8;
    --win-highlight: rgba(40, 167, 69, 0.5);
    --draw-highlight: rgba(108, 117, 125, 0.5);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

body[data-theme="dark"] {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #e4e6eb;
    --border-color: #3a3b3c;
    --accent-color: #4dabf7;
    --accent-hover: #1c7ed6;
    --board-bg: #2c2c2c;
    --cell-bg: #333333;
    --cell-hover-bg: #3d3d3d;
    --p1-token-color: #ff6b6b;
    --p2-token-color: #4d96ff;
    --win-highlight: rgba(26, 179, 105, 0.5);
    --draw-highlight: rgba(134, 142, 150, 0.5);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* --- General Styles --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: grid;
    place-items: center;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.game-container {
    background-color: var(--container-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    width: 90%;
    max-width: 500px;
    text-align: center;
    transition: background-color 0.3s ease;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

/* --- Theme Toggle --- */
#theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}
#theme-toggle:hover {
    background-color: var(--board-bg);
}
#theme-toggle::before {
    content: '☀️'; /* Sun icon */
    font-size: 20px;
    color: var(--text-color);
}
body[data-theme="dark"] #theme-toggle::before {
    content: '🌙'; /* Moon icon */
}


/* --- Player Info & Status --- */
.player-info-container {
    display: flex;
    justify-content: space-around;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.player-card {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.player-card[data-my-turn="true"] {
    border-color: var(--accent-color);
    box-shadow: 0 0 10px var(--accent-color);
    transform: scale(1.05);
}

#p1name { color: var(--p1-token-color); font-weight: 600; }
#p2name { color: var(--p2-token-color); font-weight: 600; }

#game-status {
    margin-bottom: 1rem;
    font-size: 1.1rem;
    font-weight: 600;
    height: 25px; /* Reserve space to prevent layout shifts */
}

/* --- Game Board --- */
.board-container {
    margin-bottom: 1.5rem;
}

#board {
    border-collapse: collapse;
    margin: 0 auto;
    background-color: var(--board-bg);
    border-radius: 8px;
    overflow: hidden;
}

#board td {
    width: 110px;
    height: 110px;
    border: 4px solid var(--board-bg);
    text-align: center;
    vertical-align: middle;
    font-size: 4rem;
    font-weight: 700;
    cursor: pointer;
    background-color: var(--cell-bg);
    transition: background-color 0.2s ease;
}

#board td:hover {
    background-color: var(--cell-hover-bg);
}

#board td.✖ { color: var(--p1-token-color); }
#board td.Ｏ { color: var(--p2-token-color); }

#board td.highlight {
    background-color: var(--win-highlight);
}
#board.draw-board {
    background-color: var(--draw-highlight);
}

/* --- Controls --- */
.controls-container {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.control-btn {
    background-color: var(--accent-color);
    color: #ffffff;
    border: none;
    border-radius: 8px;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.2s ease;
}
.control-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
}
.control-btn:active {
    transform: translateY(0);
}

/* --- Settings Panel (Modal) --- */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: grid;
    place-items: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}
.overlay.open {
    opacity: 1;
    pointer-events: auto;
}

.settings-panel {
    position: relative;
    background: var(--container-bg);
    padding: 2rem;
    border-radius: 12px;
    width: 90%;
    max-width: 400px;
    box-shadow: var(--shadow);
    transform: scale(0.95);
    transition: all 0.3s ease;
}
.overlay.open .settings-panel {
    transform: scale(1);
}

.settings-panel h2 {
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--accent-color);
}
.setting-group {
    margin-bottom: 1.5rem;
}
.setting-group h3 {
    margin-bottom: 0.75rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.25rem;
}
.settings-panel label {
    display: block;
    margin-bottom: 0.25rem;
    font-weight: 600;
}
.settings-panel input[type="text"] {
    width: 100%;
    padding: 0.5rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
}
.ai-toggle {
    display: flex;
    align-items: center;
    margin-top: 0.5rem;
}
.ai-toggle input[type="checkbox"] {
    margin-right: 0.5rem;
    width: 18px;
    height: 18px;
}
.apply-btn {
    width: 100%;
    margin-top: 1rem;
}
.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-color);
    cursor: pointer;
}

/* --- Responsive Design --- */
@media (max-width: 550px) {
    h1 { font-size: 2rem; }
    #board td {
        width: 80px;
        height: 80px;
        font-size: 2.8rem;
    }
    .game-container { padding: 1.5rem; }
}